1. In a large pot melt butter over medium heat. Add marshmallows and stir until completely melted. Remove the marshmallow mixture from the heat.
2. Add rice krispie cereal. Stir until the cereal mixture is well combined.
3. Using a rubber spatula or wax paper evenly press mixture into a 9 x 12 inch baking dish coated with nonstick spray.
4. In a medium microwave safe bowl melt the chocolate chips and coconut oil. Heat in the microwave at 15 second intervals, stirring in between until the chocolate is completely smooth.
5. Spread the chocolate over the peanut butter rice krispies and place the dish in the fridge to cool for an hour.
6. When the chocolate has completely hardened, remove the rice krispie from the pan and cut into 2" bars.